The present invention relates to an image forming apparatus (for example, an electrophotographic apparatus) with a replaceable part such a developing unit.
Generally, an electrophotographic image forming apparatus such as a printer, copier or facsimile machine is configured to form an image by uniformly charging a surface of a photosensitive body, exposing the surface of the photosensitive body to form a latent image, developing the latent image using a toner (as a developer) to form a toner image, transferring the toner image to a recording medium, and fixing the toner image to the recording medium.
The image forming apparatus has a replaceable part such as a developer cartridge or a developing unit detachably attached to a main body of the image forming apparatus. Recently, there is proposed a replaceable part having a memory (i.e., a storage portion) for storing information of the replaceable part.
Information is transferred between the memory and the main body of the image forming apparatus using a contact-type transferring method or non-contact-type transferring method. In the contact-type method, a contact portion of the memory and a contact portion of the main body of the image forming apparatus are brought into contact with each other with a biasing force for ensuring electrical connection therebetween. The contact portions are subjected to gold plating in order to prevent oxidization of the contact portions (see, Patent Document No. 1).    Patent Document No. 1: Japanese Laid-open Patent Publication No. 2007-271895 (paragraphs 0022-0023, FIG. 8)
However, when the replaceable part is attached to or detached from the main body of the image forming apparatus, there is a possibility that the contact portion of the main body of the image forming apparatus may contact a portion of the replaceable part other than the contact portion. In such a case, the gold-plating of the contact portion may be abraded, scratched or broken, with the result that information is not correctly transferred between the memory and the main body of the image forming apparatus.